The Specific Aims of Core B (Pathology) are: 1. To provide necropsy, histology, immunohistochemical, and in situ hybridization services to program investigators. 2. To identify, collect, and evaluate human oropharyngeal specimens that are likely to be involved by naturally occurring human EBV and KSHV infections. 3. To develop new immunohistochemical tests for EBV and KSHV protein markers that permit detection of infected cells in paraffin- embedded non-human primate and human tissue specimens. 4. To create a single entity responsible for expert review of all pertinent human and animal model pathology, and thereby serve as a point of integration and dissemination of data accrued in each of the projects. The Core will be central to the pathologic evaluation of oropharyngeal tissues in rhesus LCV (Project 1) and rhesus RRV (Project 2) infections, being responsible for the collection, storage, processing, staining, and interpretation of oropharyngeal samples obtained through serial biopsies or at necropsy. An additional aim of projects 1 and 3 is to identify oropharyngeal sites of human herpesvirus infection. In order to accomplish the Core will collect, process, and evaluate human oropharyngeal tissue samples (obtained at the time of autopsy, as discarded biopsy specimens, or as biopsies obtained specifically for this purpose from human and optimizing new immunohistochemical tests (using the antibodies created in the Antibody Core) that detect herpesvirus antigens in paraffin-embedded tissue sections, thereby permitting the identification of cell populations infected by EBV, LCV, KSHV, and RRV. By identifying sites of active infection and T cell response, the Core will contribute to the optimal sampling of sites for evaluation of the mucosal immune responses in KSHV, LCV, and EBV infections (Project 4). Finally, as the sole entity responsible for evaluation of pathologic findings across all of the participating projects, the Core will facilitate the transmission of data dn protocols among project investigators.